Problem
A school is trying to take an annual photo of all the students. The students are asked to stand in a single file line in non-decreasing order by height. Let this ordering be represented by the integer array expected where expected[i] is the expected height of the ith student in line.
You are given an integer array heights representing the current order that the students are standing in. Each heights[i] is the height of the ith student in line (0-indexed).
Return **the *number of indices* where **heights[i] != expected[i].
Example 1:
Input: heights = [1,1,4,2,1,3]
Output: 3
Explanation:
heights: [1,1,4,2,1,3]
expected: [1,1,1,2,3,4]
Indices 2, 4, and 5 do not match.
Example 2:
Input: heights = [5,1,2,3,4]
Output: 5
Explanation:
heights: [5,1,2,3,4]
expected: [1,2,3,4,5]
All indices do not match.
Example 3:
Input: heights = [1,2,3,4,5]
Output: 0
Explanation:
heights: [1,2,3,4,5]
expected: [1,2,3,4,5]
All indices match.
Constraints:
1 <= heights.length <= 1001 <= heights[i] <= 100
Solution
/**
* @param {number[]} heights
* @return {number}
*/
var heightChecker = function(heights) {
var arr = Array.from(heights).sort((a, b) => a - b);
var count = 0;
for (var i = 0; i < heights.length; i++) {
if (heights[i] !== arr[i]) {
count += 1;
}
}
return count;
};
Explain:
nope.
Complexity:
- Time complexity : O(nlog(n)).
- Space complexity : O(n).